cannot recieve email

Have added some domains and mailboxes.
I can send mails using squirrelmail.
but if i reply to that mail or send a mail to that account, its not recieved.

THe mail is returned to gmail with this error

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 5.1.1 <isptest@*******.net>: Recipient address rejected: User unknown in local recipient table (state 14).

In the database "dbispconfig" table "mail_user" the mailbox users are shown.
but I noticed that in the table "mail_user" thers a field "access" which is a boolean (y/n) and is "n" by default for all users.

Also theres a table "mail_access" which has no user(no records) in it.